The present invention relates to an apparatus for washing a substantially disk-shaped workpiece such as a magnetic disk substrate, an optical disk substrate, a silicon wafer, or a glass wafer.
A scrubbing-type washing apparatus for washing a substantially disk-shaped workpiece by means of a roll-shaped washing member is known as those disclosed, for example, in Japanese Unexamined Patent Application Publications Nos. 9-206705 and 10-80668. These washing apparatuses wash the workpiece by bringing the both surfaces of the workpiece into contact with washing rollers while causing forced rotation of the workpiece by supporting the outer periphery of the workpiece by a plurality of driving rollers and spraying a washing solution from a jet nozzle on the workpiece.
However, the conventional washing apparatus using washing rollers is of a type in which workpieces are washed while feeding the workpieces one by one to the washing section, resulting in the disadvantage of poor throughput. For example, when washing 50 workpieces, the period from the start of washing of the first workpiece to the completion of washing of the 50th workpiece is very long, and when the preceding process is a batch processing process treating a large number of workpieces at once, this tends to result in a reduction in quality such as deterioration of the machined surfaces of the workpieces while waiting for washing.
A main technical object of the present invention is to provide an efficient and productive roller-type washing apparatus which permits simultaneous washing of a plurality of workpieces.
To achieve the aforementioned object, the invention provides a disk-shaped-workpiece washing apparatus comprising a carrier which holds a plurality of disk-shaped works in a longitudinal arrangement at predetermined intervals, a washing section which scrubs the workpieces held by the carrier sequentially in groups of a plurality of the workpieces, and an intermittent transfer mechanism, wherein the washing section comprises a lifting mechanism which removes the plurality of workpieces to be washed from the row of workpieces held by the carrier in groups of a plurality of the workpieces to corresponding washing positions, driving means which are provided at the corresponding washing positions, and forcedly cause the workpieces to rotate around the axes lines by coming into contact with the upper outer periphery of the lifted workpiece, and a pair of drivable and rotatable washing rollers provided for each of the washing positions which washes each workpiece while holding each rotating workpiece in between from the both sides thereof.
In the washing apparatus of the invention having the aforementioned configuration, the plurality of workpieces held in parallel on the carrier are lifted to the washing position by the lifting mechanism in groups of a plurality of the workpieces, and each workpiece is scrubbed and washed by the pair of washing rollers. Upon the completion of washing of a first group of workpieces, the carrier is moved by the spacing of the workpieces arranged in parallel, and washing of a second group of the workpieces is conducted in the same manner as above. By repeating the same operations a prescribed number of times, washing of all the works held by the carrier is completed.
According to the invention, as described above, advantages are provided in that it is possible to sequentially wash a plurality of works with washing rollers having a diameter larger than the spacing of the workpieces arranged in parallel by washing the plurality of works held at small spacings in a carrier by extracting the workpieces in groups of a plurality of the workpieces, thus achieving a higher throughput with a very high efficiency and an excellent productivity as compared with the conventional art of washing workpieces while transferring the workpieces one by one.
According to a preferred embodiment of the invention, the washing positions of the plurality of workpieces are alternately provided at different heights, the driving means and the washing rollers at each washing position are also arranged alternately at different heights, and adjacent washing rollers at adjacent washing positions overlap each other one above the other.
As a result, the spacing between adjacent washing positions can be reduced, and more workpieces can be washed at one time.
According to another preferred embodiment of the invention, each pair of washing rollers provided at each washing position is arranged horizontally at a position crossing the center portion of the workpiece in the diameter direction, and serves as pressing means for pushing up the workpiece and pressing the workpiece against the driving means by the use of a rotational force acting during washing.
As a result, it is no longer necessary to provide a special supporting roller rotatably supporting the workpiece during washing, leading to a washing apparatus of a simpler configuration.
According to a concrete embodiment of the invention, the washing apparatus has a washing tank filled with a washing solution, and the carrier and the washing rollers are immersed in the washing solution in the washing tank so as to permit washing of the workpiece in the washing solution.
According to a preferred concrete embodiment of the invention, the driving means comprises an endless driving belt arranged so as to come into linear contact with the upper-end outer periphery of the lifted workpiece along the circumference thereof.
According to another preferred concrete embodiment of the invention, the lifting mechanism is provided with a plurality of lifting arms, which synchronously moves up and down, arranged at predetermined intervals under the position where the carrier is provided in the washing section, and a supporting groove engaging with the outer periphery of the lower end of the workpiece held upright by the carrier is provided at the upper end of each lifting arm.
FIG. 1 is a sectional view schematically illustrating the washing apparatus of the present invention;
FIG. 2 is a side view from the right illustrating the washing apparatus shown in FIG. 1 cut away at the position of the washing section;
FIG. 3 is a partially enlarged view of FIG. 2;
FIG. 4 is a partially enlarged view of FIG. 1;
FIG. 5 is a partially enlarged view of FIG. 3;
FIG. 6 is a side view of the transfer in/out mechanism of the carrier; and
FIG. 7 is a partially cutaway side view of the carrier.